Relationship between Brain Glucose Metabolism and Weight Loss

What happens to the brain during hyperinsulinemia in overweight patients?…

In healthy patients the brain glucose metabolism does not increase during hyperinsulinemia. However, in obese patients associated with impaired glucose tolerance and peripheral insulin resistance, brain glucose metabolism increases during hyperinsulinemia. This study determined whether weight loss after bariatric surgery can reverse brain glucose metabolism abnormality during high insulin levels in blood.

The study included 22 morbidly obese patients and 7 healthy patients as control subjects. Brain glucose metabolism was assessed once for healthy patients and twice before and after 6 months after bariatric surgery. [18F] flurodeoxyglucose scanning was used to measured brain glucose metabolism during insulin stimulation and fasting condition.

The results have shown there was no difference in brain glucose metabolism in either group during fasting. However, brain glucose metabolism was significantly higher in obese patients during insulin stimulation than in control patients before bariatric surgery. After 6 months of bariatric surgery, increased brain glucose metabolism in obese patients was significantly reduced.

In conclusion, weight loss after bariatric surgery can improve peripheral insulin sensitivity and diminish the elevation of glucose metabolism during hyperinsulinemia for morbidly obese patients with impaired glucose intolerance.